Deterministic symbol existence for PyPI and npm packages: functions, classes, methods, constants with signatures and deprecation flags, extracted from real artifacts. Negative answers include closest matches and signed proof. $0.005 USDC per check.
# 1. Ask the endpoint what it costs (no payment, no wallet needed): curl -i -X GET 'https://attester.dev/v1/symbol/exists' # -> HTTP/1.1 402 Payment Required # the response carries the price, asset and pay-to address. # 2. Pay and retry with any x402 client: npx x402-fetch 'https://attester.dev/v1/symbol/exists'
Endpoint: https://attester.dev/v1/symbol/exists. Operated by attester.dev, not by Animica. Price and availability were correct at the last probe on 2026-08-31 and are set by the operator, who may change them.
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